CStone Pharmaceuticals said it intends to buy back as many as 136.45 million shares on the open market under the general repurchase mandate approved at the 25 June 2025 annual general meeting and any future mandates.

The repurchases will be conducted in accordance with Hong Kong Stock Exchange Listing Rule 10.06, which restricts buybacks during periods when the company is in possession of undisclosed inside information or within 30 days before the release of periodic results. CStone expects the programme to begin after it presents new clinical data on its core asset, CS2009 (a PD-1/VEGF/CTLA-4 trispecific antibody), at the upcoming American Society of Clinical Oncology (ASCO) Annual Meeting.

Management and the board said the initiative reflects confidence in the company’s research achievements, commercial progress and long-term development, while aligning capital deployment with shareholder-return priorities. The timing, volume and price of any repurchases will depend on market conditions and remain at the board’s discretion.

Founded in 2015, CStone has brought four innovative drugs to market and obtained 21 new drug application approvals across nine indications. The company’s pipeline comprises 16 candidates, including antibody-drug conjugates, multispecific antibodies, immunotherapies and precision medicines.

Investors are advised that execution of the repurchase plan is not guaranteed and to exercise caution when dealing in CStone shares.